This invention relates to a vortex motion phase separator for liquid transfer in a zero gravity environment.
Heretofore, the transfer of liquid from one container to another in a zero gravity environment has been accomplished by the use of a bladder. Bladders are not considered suitable for cryogenic liquids because of insufficient flexibility at cryogenic temperatures.
Transfer can also be accomplished in a zero gravity environment where the container is being accelerated by rocket engines and the tank is being pressurized with inert gas to force the liquid out. However, this known pressurization technique will not work satisfactorily when the container is not experiencing acceleration because, without any gravitational or acceleration force, globules of the liquid merely collect in various areas of the container and are not forced out by the inert gas.
Another disadvantage in using inert gas to force the liquid from the container is that such is added to the weight of the container due to the requirement for storing the inert gas. There also has to be some means for regulating the pressurized gas in order to prevent overpressurization of the containers.
The main problem in transferring a liquid in a gravity-free environment is that the liquid will separate into globules and will float throughout the container. While it is possible to accelerate and decelerate the container in order to collect and transfer the liquid, it is not practical to do so since it requires the use of the engines of the space vehicle and the consumption of fuel for operating such engines in order to provide such acceleration or to decelerate the container.
One attempt to resolve this problem is found in U.S. Pat. No. 3,744,738 issued to applicant on July 10, 1973. The liquid transfer device disclosed in this patent overcomes most of these problems by providing a transfer screen which is contained within the sender tank. The transfer screen includes a spiral-shaped member carried within the sender tank having a longitudinal axis in alignment with the exit port of the sender tank from which the liquid is being carried. The spiral-shaped member has a diameter corresponding to the internal diameter of the sender tank, and means are provided for rotating the spiral-shaped member so that the pressure created by the rotating screen pushes the liquid in the sender tank out,the exit port. A perforated screen is used so that when a back pressure is created which is greater than the pressure that the spiral-shaped screen member can withstand, the perforations in the screen member allow the liquid to pass through the spiral-shaped screen member, thereby minimizing the back pressure. The disadvantage of the device in this patent is that it requires hardware to be disposed within the tanks which is difficult to maintain and the screens within the tank add weight to the vehicle when it is in a gravity environment.